The Tissue Array Research Program (TARP) focuses on the use of tissue microarrays (TMAs) in biomedical research. TMAs are collections of samples of formalin fixed, paraffin embedded tissue from tens to hundreds of patients on a single microscope slide for high throughput analysis of protein expression most often by immunohistochemistry. The TARP Lab focuses on production and application of TMAs for cancer research. The studies utilizing TMAs are typically identified at the identification of biomarkers for diagnosis, prognosis and prediction of response to therapy for cancer. A wide diversity of cancer types are studied as collaborative efforts in the TARP Lab, including melanoma, breast, colon, lung, ovarian, prostate, pancreas, bladder, and renal cancers. Preclinical specimen types include cancer cell lines and xengrafts, including xenografts of pediatric tumors. TMAs are constructed of normal tissue, premaligant (dysplastic) and cancer specimens. The TARP Lab investigates quality issues pertaining to surgical pathology diagnostic samples in the form of formalin fixed paraffin embedded tisue, the most common source material for surgical pathology diagnosis in clinical care, as well as use in TMAs. Defining and refining quality parameters in pathology specimens is an essential element of development of robust clinical tissue based biomarkers.